Some methods of manufacturing a memory cell array having a three-dimensional structure involve forming a hole in a stacked body in which different types of materials are alternately stacked. However, when a bit density of the memory cell array is high and there is a corresponding large amount of stacked material, and the stacked body becomes thicker, the hole may have a high aspect ratio. In etching for forming a hole having a high aspect ratio, an amount of etching of a mask is also increased, and thus the mask may, in some cases, be readily deformed. The deformation of the mask affects the shape and dimensions of the hole formed in the stacked body.